MEGAPTERA. 



67 



mostly horizontal, but depressed at Eustachian end. 

 Keel not pi'ominent, blends gently with adjoining 

 inner and outer surfaces. See figures below. 



The Periotic with large auditory foramina on the 

 cerebral aspect, and on the tympanic surface a 

 fenestra ovalis with stapes attached. Inferior surface 

 smooth, convex, formed of dense bone, continuous 

 with a mass of more cancellated bone for attachment 

 to the skull.] 



